Molecular sieves of the crystalline zeolite type are well known in the art and now comprise over 250 species of both naturally occuring and synthetic compositions. In general, crystalline zeolites are aluminosilicates whose frameworks are formed from AlO.sub.4 and SiO.sub.4 tetrahedra joined by the oxygen atoms and characterized by the pore openings of uniform dimensions, having significant ion-exchange capacity and being capable of reversibly desorbing an adsorbed phase which is dispersed through the internal voids of the crystal, without displacing any atoms which make up the permanent crystal structure.
Zeolite-Y is isostructural with the mineral faujasite and Zeolite-X, an aluminum rich variant of Zeolite-Y. It contains large, near spherical cages with a free diameter of 1.3 nm. Each supercage is connected tetrahedrally with four neighboring supercages via 12-membered ring windows with a crystallographic diameter of 0.74 nm. For most molecules except very bulky ones, Zeolite-Y offers a spacious cage and pore system through which they can diffuse without hindrance. The general chemical formula of the synthetically produced, anhydrous, large pore, Zeolite-Y expressed in terms of moles may be as follows: 1.0.+-.0.2 Na.sub.2 O:Al.sub.2 O.sub.3 :nSiO.sub.2 ; wherein `n` has values from 3 to 7. These are commercially more useful as adsorbents and they have proven to be more stable at high temperature in the presence of moisture than Zeolite-X; this may be attributed to their high silica/alumina ratio.
Zeolite-Y has multifacet applications and are being best employed as catalyst in vapor phase cracking of petroleum (Weitkemp), J., Ernst S., in Chemicals in the oil industry: development and application (Ed. P. H. ogden), Royal Society of Chemistry, Cambridge, 1991), Fluid Catalytic Cracking (Biwaaaas, J., and Maxwell, I. E., Appl.Catal, 1990 (63), 197), is omerization of light gasoline (Maxwell, E. G. Catalysis today, 1987 (1), 385) and hydrocracking of vacuum gas oil (Ward, J. W. in `Preparation of Catalysts` (Eds: G. Poncelet, P. Gronge and P. A. Jacobs) Studies in surface. Science and Catalysis, Elsevier, Amsterdam oxford, N.Y.&lt;1983 (1) 587). Treatment of wastewater with zeolite specifically with zeolite-Y is increasing world-wide; work in progress seeks to extend the use of zeolites for removal of isotopes (Dyer. A., Chem Ind., 1984, 241-245); long term disposal techniques and composites. Nevertheless, the development of material with interesting electrical, mechanical or other properties from zeolites has not often been reported in literature.